1. Field of the Invention
This invention is generally directed toward an internal bracing system for the knee, shoulder, ankle or the like. The internal bracing system is designed to be located on the medial, lateral, anterior, or posterior aspect of the joint in a manner effective to control excessive laxity or traumatic rotatory and/or translational instability of the joint. The invention is more particularly directed toward an internal bracing system having an extra-articular tension band mechanism and anchoring assembly. The anchoring assembly is designed to affix a tethering device to various bony structures which form a joint.
2. Discussion of Related Art
It has been observed that subsequent to specific joint instabilities after ligament injury, trauma or chronic laxity (which can be more common in certain populations with high demands and genetic pre-disposition); there is a need for specialized internal bracing or ligament augmenters. Specifically, as seen in these populations, there can be severe combined ligament insufficiency and/or deficiencies leading to instability of the joint causing early progressive joint wear, arthritis, pain and dysfunction.
Existing externally worn joint braces have been used for years but have been uncomfortable and ineffective in providing the type of control and stability needed to control pathologic sequele of an unstable joint. The other traditional option of intra-articular ligament replacements are complex to install, have high failure rates and are generally not effective over time. Thus, there has been a general failure of external brace capacity and surgical intracapsular (complex positioning required) ligament reconstructions to control the high joint functional demands, e.g. control of the unstable motion and/or joint slippage or control the buckling or subluxation at high speed/stress motions causing the joint to still give away.
As a result of these observations, the present inventors have sought to restabilize the effected joints, by providing to these stretched or torn ligaments, augmenting or reinforcing structures, for example to extra capsular knee structures, thereby providing an ‘internal bracing’ like structure which can be surgically created by a simple, low-cost technique. This robust extra-capsular augment or internal bracing of the joint controls stability using simple artificial reinforcers or tension bands. This is done through this invention's ability to control the articular position of the particular joint allowing this to return to a more normal motion, while simultaneously limiting the abnormal translations and rotations, and thereby lessening abnormal stresses.